The invention relates to a method and composition to treat boiler water. More particularly, the invention relates to a method of treating boiler water by adding a composition comprising an ester of a hydroxy amine and an acid in an amount effective to treat boiler water and related condensate.
A boiler requires extremely pure water in order to avoid a plurality of different problems. Unfortunately, water coming into most boilers is not pure enough to avoid these problems. Impurities in the water, including gases such as oxygen and carbon dioxide, would rapidly contaminate the water and damage the boiler.
In addition, condensed steam, referred to as condensate, generated in the boiler and accompanying boiler lines, is a major source of impurities. Condensate generally traps impurities, especially gases including oxygen and carbon dioxide, from the air and becomes contaminated. The contaminated condensate inevitably reenters the pool of boiler water, thereby further contaminating the boiler water. Other problems including accumulation of scale, maintenance of pH, boiler pitting by oxygen, and the generation of carbonic acid in the water may occur as a result of contaminated boiler water. Therefore, the contaminants must be removed or treated.
Currently there are a variety of different physical and chemical treatments for contaminated boiler water. Conventional treatments have included the use of amines, particularly to scavenge oxygen and neutralize carbon dioxide. These amines are generally volatile, having boiling points comparable to elevated temperatures in the boiler, and vaporize into the steam to treat the resulting condensate.
Amines which have been used treat boiler water include octadecylamine, typically used as a filming amine, and diethylaminoethanol which has also been used to treat condensate systems. However, these amines, as well as other conventional amines commonly used as boiler water treatment agents, typically are commercially available only as liquids. In addition, the prior art boiler water treatment compositions containing amines were prepared and stored as liquids. As with most liquid amines, these compositions generally emit repugnant and potentially toxic odors which may be detected during manufacture, packaging, or shipping processes, and particularly during the use in treating boiler water. In addition, prolonged storage of liquid amines generally allows the vapor pressure to build exposing the user to serious noxious odors and unhealthy levels of vapors. Such amines and corresponding compositions, therefore, pose possible health and safety risks to the user and are likely to affect any person involved with the processing of such boiler treatment agents who may be exposed to the odors and vapors. Therefore, there exists a need to relieve the odor generated by liquid amine boiler water treatment compositions. There also remains a need to improve the formulation of the amine used to treat boiler water and to improve the ease and comfort by which the amine may be used to treat boiler water.
The present invention reduces or eliminates amine odors and corresponding safety risks by providing a method and composition to treat boiler water by adding an effective amount of an amine which has been modified in form. Modified amines, such as an ester of a hydroxyamine, provide effective treatment of boiler water systems without exposure of the user or processor to repugnant amine odors and vapors which may threaten health and safety. Modified amines generally provide a more convenient solid form in which the amine may be used to treat boiler water.
Esters of hydroxyamines may be formed by reacting a hydroxyamine, partially or fully, with an acid. For instance, an amino-phosphate or phosphonate ester may be formed by reacting a hydroxyamine with a phosphoric acid or phosphonic acid respectively. Similarly, amino-sulfate and amino-sulfonate esters may be formed by reacting a hydroxyamine with a sulfuric acid or a sulfonic acid respectively. The ester may have a hydroxyamine to acid mole ratio in the range of from about 1:1 to about 19:1, preferable greater than about 3:1. Such hydroxyamine-acid ester mixtures generally reduce or eliminate amine odors and allow the amine to be added to the boiler water in a solid form for convenience and comfort of use. Alternatively, the ester may be combined with other treatment agents which may be added in an effective amount to treat the boiler water.
Hydroxyamine-acid esters are effective as boiler water treatment agents because they generally decompose at elevated temperatures, such as boiling temperatures, at atmospheric pressures to a sufficient extent to release effective amounts of the individual components, i.e., a hydroxyamine and the corresponding acid. A variety of hydroxyamines, such as N,N-diethylaminoethanol, 2-amino-2-methyl-1-propanol, 1,1-dimethylamine-propanol, 2-dimethylamino-2-methyl-1-propanol, and core amines, such as cyclohexylamine, morpholine, octadecylamine, and N,N-dimethyl-1,3-propanediamine, modified to include terminal hydroxy groups may be used to form the ester to treat the boiler water.
The ester may be formulated into either a liquid or a solid, as desired, and added directly to treat the boiler water. Both the liquid and the solid formulations are generally free of odors and solid compositions may allow easier use and storage. The treatment composition can generally be provided at high concentrations for storage and application and is effective at concentrations determined by the user and dependent on the desired level of treatment.
The ester is generally formulated with at least one other component to form a final treatment composition to effectively treat boiler water. For instance, the composition may include additional oxygen scavenging agents, alkalinity control agents, hardness reducing agents, and iron controlling agents. If the desired treatment composition is to be formulated as a solid, such as a dry powder, then each of the other components are generally mixed in a dry form with the hydroxyamine-acid ester. Effective quantities of each component may be determined by the user depending upon the type and level of contamination and desired treatment concentration. The boiler water treatment composition may generally be stored and applied at high concentrations or pre-mixed dilutions which may be added at effective concentrations determined by the user.
The present invention will be further appreciated in light of the following detailed description.